High frequency speaker baffle



Jan. 14, 1958 B. w. LOWELL HIGH FREQUENCY SPEAKER BAFFLE Filed May' 25,1955 2,819,773 Patented Jan. 14, 1958 ice HGH FREQUENCY SPEAKER BAFFLEBenjamin W. Lowell, Richmond Heights, M0.

Application May 23, 1955, Serial No. 510,382

11 Claims. (Cl. 181-31) This invention relates to improvements inspeaker bailles, and in particular is concerned with a non-resonant,high frequency baille.

rThe present invention is an improvement on my patent for Loud SpeakerMounting, No. 2,563,948, issued August 14, 1951. The baille of thisinvention has extremely faithful reproducing characteristics for thehigher audio frequencies when the battle is used in loud speaker systemsand the like. The baille is especially well adapted for use as arecessed ceiling baille in buildings and the like, and is characterizedby an undercoating on the battle frame which prevents resonance andeliminates undesirable vibrations.

By means of this invention, the speaker baille can be used with astandard speaker cone to distribute the desired sound at diilerentangles from the axis of the speaker with extremely high faithfulness inthe higher as well as the lower frequencies at different directions fromthe axis. The entire baille structure is made as a unit that can beconveniently shipped and installed in a simple and expedient manner.When used in a ceiling, or other supporting structure, the baffle servesin an improved manner and is strong, rigid and relatively inexpensive.

Therefore, it is a principal object of this invention to provide aceiling speaker baille which has characteristics of faithfullyreproducing high frequencies at different directions from the axis ofthe speaker through the provision of baflle rings, without metallicresonance.

Still another object of this invention is to provide a speaker baillehaving a central diffuser with a plurality of spaced rings whichdisperse the sound waves from the speaker to obtain a high frequencyreproduction.

Yet another object of this invention is to provide a speaker baillehaving a central diffuser and a plurality of spaced rings set atdifferent angles from one another at an increasing pitch towards thecenter of the baffle to provide for a most effective sound reproduction.

Still a further object of this invention is to provide a speaker baillein which undesirable resonance and vibrations are reduced by asponge-like undercoating on the baille supporting structure.

Yet another object of this invention is to provide a speaker baillehaving a diiluser and a plurality of spaced dispersion rings in whichthere are supporting rods through these elements which are held out ofcontact therewith by vibration reducing grommets of a resilient naturefor the reduction of resonance and vibration.

Still another object of this invention is to provide a speaker bailleapparatus having high frequency characteristics with reduced resonanceand vibration which is rugged and simple to construct and install.

Further objects of this invention will appear in the detaileddescription which follows and will be further apparent to those skilledin the art.

A preferred embodiment of the invention is shown in the accompanyingdrawings for the purpose of illustration. It is to be understood thatthe invention is not limited thereto, and that these drawings are forthe purpose of example only. ln the drawings:

Figure 1 is a View in front elevation of the speaker baille;

Figure 2 is a view in rear elevation of the speaker baille with theundercoating partially removed;

Figure 3 is a view in cross section of the baille taken on the line 3 3of Figure 2; and

Figure 4 is a view taken similarly to Figure 3 on an enlarged scaleshowing a fragmentary portion of the baille and the means for connectingthe dispersing rings.

The speaker baille is generally indicated at 10 in Figures 1, 2 and 3,and has as its main supporting element a frame 11. Supporting rods 12and 13 connect dispersing rings 14 and 15 to the central diffuser cone16. A speaker 17 is indicated in dotted lines as being fastened to theframe.

The frame 11 is of a generally rim-like configuration and is constructedof spun aluminum which has desirable characteristics for corrosionprevention and negligible vibration. As best shown in Figure 3, theframe 11 has an exterior flange 2G and interior ledges 21 and 22 offsetat levels rearwardly from the outside annular surface 23. The ledges 21and 22 are defined by shoulders 24 and 25. Bosses 26, 27, 28 and 29 arestamped into the shoulder 25 to provide for the insertion of rods 12 and13.

An undercoating 31 is provided on the interior of the annular surface23, the shoulder 24 and the ledge 21. This undercoating provides for thesubstantial elimination of any vibration and resonance in the speakerbaille, and acts to absorb any forces that might be transmitted to theframe or sound waves from the speaker. The undercoating is of a more orless sponge-like nature but is relatively hard, although it will bear animpression when a hard object is inserted against it. Such anundercoating may be conventionally made of fibers, tar and oil, whichact as a metallic deadener when applied to the frame.

The diffuser 16 is of the same type as that disclosed in my Patent No.2,563,948, but is supported by the two rods 12 and 13 which passentirely through it and which are fastened at their ends on the frame11. The rods 12 and 13 are supported by rubber or soft plastic grommets3S which are fastened in bosses 36 stamped in the diffuser shell. Thisprovides a convenient manner of support for the grommets which enclosethe rods and prevent any metallic contact with the diffuser, therebypreventing vibration and resonance.

The interior ring 15, as best shown in Figure 3, is of a generallyfrusto-conical configuration. It is supported upon the rods 12 and 13 bybosses 41 stamped in its periphery. These bosses have their circularedges supported within the ilanges of the grommets 35. It will be notedthat the pitch of the boss is more nearly vertical than that of the ringsurface, which provides for a tighter and better suport for the grommetand the rod which pass through the interior thereof. It will also benoted that the bottom of the ring 15 is substantially ilush with thebottom of the dilluser 16, while the top is just slightly below the apexof the diffuser. Also, the pitch of the ring 15 is slightly greater thanthe side walls of the diffuser in order to provide for better dispersionof the sound waves and enhance the reproduction of the high frequencyalong the axis of the speaker.

The exterior ring 14 is shown in Figure 3 as being spaced from the ringl5 a lesser distance than the spacing between the ring 15 and the wallof the diffuser 16. Also, the pitch of the ring 14 is less than thepitch of the ring 15 so as to provide for eilective lateral dispersionof astagrrs thesound waves away from the axis without interferenceAssembly and operation The speaker baffle with the above describedcomponents is easily assembled. The frame 11 with its undercoating iseasily connected to the rings 14 and 15 and to the diffuser 16 insertingone of the rods 12 or 13 through the bosses 26 in the frame, the bosses42 in the exterior ring 14. the bosses 4l in the interior ring 15,andthe bosses 36 through the difiuser and the opposing bosses on theopposite sides. The grommets 35 in these bosses provide for a snug andsecure fastening` after which `the rod is secured to the frame byfastening nuts 44 to the threaded ends. The remaining rod is thenlikewise inserted through the frame. the exterior ring 14, theinteriorrin'g 15 and the diffuser 16. This completes the assembly of thebaffle.

The speaker cone shown in dotted lines at 17 in Figure 3 may be easilysecured to the ledge 22 by bolts 51. The bolts 51 mav be assembled withthe speaker bathe previously and held in place by Tinnerman nuts 52. ifdesired. This presents a baffle unit which is complete and ready foroperation when the conventional securing ofthe speaker cone and theelectrical attachments are made. The annular surface 23 can then besecured to fa wall or 'the kceiling or other support by fastening boltsor screws through openings 53, as will be readily understood.

The speaker baffle of this invention has been found to have a veryefficient frequency response in the range of 60 yto 10.000 cycles.Further, the high frequency response has been found to be veryLeffective un to angles of `60 from `the axis of the speaker. Thisfaithfulness of reproduction of the frequencies in the audio range, andparticularly the high frequencies in Ya `high faithfulness ofreproduction, is extremely advantageous `as the sound reproduced may `be'correctly heard within the zone of from zero vto 60 from `the 'speakeraxis. The arrangement of the rings 14.and has been found to vdispersethe `sound in a highly efficient 2manner without trapping of the `loudspeaker :and without any bouncing or retiection of sound waves whichwould be highly undesirable.

The provision of lthe `speaker bafe with its rings and undercoatingmakes available a unit which has long lasting qualities `fromttl-reconstruction Aof spun aluminum and which has negligible vibrationand resonance. Further, because of the `vintegral relationship of thebaffle unit, a speaker can :be `easily attached and the entire unit canbe supported to 'a -ceiling in an extremely simple installation.

Various ychanges `and modifications may be made in the baffle andsupporting structure, as `will be `apparent to those skilled inthe art.Such changes and modifications within the teaching of this `inventionare :intended to be within thelscope ofthe claims appended hereto.

What is claimed is.:

1. A loud speaker baffle for use with a loud speaker cone, said baffleAhaving va `centrally located imperforate diffusing cone and annularsound wave ldispersing means surrounding said `diffusing `cone and`spaced therefrom, said dispersing meanscomprising at least one ringelement lhaving la, frusto-conical configuration.

2. .A loud .speakerbafle for use with Ya `loud speaker cone, said bafflehaving a centrally located -imperforate diffusing lcone andannularsoundwave dispersing means surrounding `said diusing cone and spacedtherefrom, said annular dispersing means comprising a plurality of concentrically spaced ring elements having a frusto-conical configuration.

3. A loud speaker baffle having a frame comprised of a flat rimintegrally connected to internal inwardly extending shoulders, acentrally located diffusing cone, sound wave dispersing meanssurrounding said diffusing cone, and means for supporting said cone anddispersing means to said frame, said support means including elementscooperating' with vibration reducing members attached to said diffusingcone, the frame shoulders and the dispersing means.

4. A loud speaker baffle having a frame comprised of a flat rimintegrally connected to internal inwardly eX- tending shoulders, acentrally located diffusing cone, sound wave dispersing meanssurrounding said diffusing cone, means for supporting said cone anddispersing means to the shoulders of said frame, and `means covering oneside of saidI frame for reducing vibration, said last named meansincluding a coating having vibration deadening qualities.

5. A loud speaker baffle having a frame comprised of a flat rimvintegrally connected to internal inwardly extending shoulders, acentrally located diffusing cone, sound wave `dispersing meanssurrounding said diffusing cone, means for supporting ysaid cone yanddispersing means to said frame, said support `means including elementscooperating with vibration reducing members atatached to `said diffusingcone, the shoulders and the dispersing means, and means covering oneside of said frame for reducing vibration, said last named meansincluding a coating 4having vibration `deadening qualities.

6. A loud `speaker baffle having a frame, a centr-ally locatedimperforate diffusing cone, sound wave dispersing means surrounding saiddiffusing cone, said dispersing means comprising a plurality offrusto-conical ring elements spaced from one another and the diffusingcone and the frame concentrically from the axis of said diffusing cone.

7. A loud speaker baffle having a frame, a centrally located diffusingcone, sound wave dispersing means surrounding said diffusing cone, saiddispersing means comprising a plurality of frusto-conical ring elementsspaced from one another and the diffusing cone and the frameconcentrically from the aX-is of said diffusing cone, said ring elementshaving a decreasing pitch from `the ring `adjacent the diffusing coneand `outwardly therefrom.

8. A loud speaker baffle `having a frame, a centrally located diffusingcone, sound wave dispersing means surrounding said diffusing cone, saiddispersing means comprising a plurality of frnsto-conical ring elementsspaced from one another and the diffusing cone and the frameconcentrically from the axis of said diffusing cone, the spacing betweenthe interior `ring element adjacent the cone, and saidcone being greaterythan the spacing between said interior `ring and the next ring.

9. A loud speaker baffle having a frame, a centrally located diffusingcone, sound wave `dispersing means surrounding said diffusing cone,`said dispersing means comprising a plurality of frusto-conical ringelements spaced from one another and the diffusing cone and the frameconcentrically from the axis of said diffusing cone, said ring "elementshaving their bases substantially flush with the base of said cone andhaving their tops progressively lower in a direction radially away fromsaid cone.

10. A loudspeaker bafe having a frame, a centrally located diffusingcone, sound wave dispersing means sur rounding said diffusing cone, saiddispersing means ycomprising rst and second lfr-ustoconical Vringelements spaced from one another and the diffusing cone and the frameconcentrically from the axis of said diffusing cone, said first ringbeing adjacent the cone and `spaced a distance greater than the spacingbetween said first and second rin s.

lg 1. A loud speaker baffle having a frame, a centrally located diusingcone, sound wave dispersing means sursaid cone, and said rst ringfurther having a greater rounding said diffusing cone, said dispersingmeans compitch than said second ring.

prising rst and second frustoconical ring elements spaced ReferencesCited in the me of this patent from one another and the diiuslng coneand the frame concentrically from the axis of said diiusing cone, saidUNITED STATES PATENTS first ring being adjacent the cone and spaced adistance 1,685,050 Gems Sept, 18, 1928 greater than the spacing betweensaid first and second 1,732,495 Brower Oct. 22, 1929 rings, said ringelements having their bases substantially 2,179,840 Bucky Nov. 14, 1939ush with the base of said cone and having their tops 2,541,946 StarkFeb. 13, 1951 progressively lower in a direction radially away from 102,563,948 Lowell Aug. 14, 1951

